Hi, I have recently purchased a Pi from Element14 along with the WiPi usb dongle they sell on their website. When I first started the Pi the usb dongle worked - it recognized the device and connected to the internet successfully. An hour later when I first rebooted the Pi the problem started - the usb wifi does not connect to the internet any more. The following are all configurations made on a fresh install. Furthermore, the problem persists after I have re-formatted the SD card and reinstalled Raspbian in an attempt to get it working (multiple times).

It seems that the adapter is recognized but is constantly scanning for networks. If I use the wpa_gui tool provided on the Desktop, the status shown is "scanning" and the scan list of networks in the popup is empty. If simultaneously I enter "sudo iwlist wlan0 scan" I mostly get "No results" but sometimes it finds the networks. When it finds them then they show in the wpa_gui scan window instantly and I can select the network and successfully connect to it... for about 1-2 minutes when it disconnects and it goes to constant scanning again. The usb device does not flash (the led is not even on) when this constant scanning is going on. It only flashes when I manage to connect to the network.

I tested the usb WiFi device in Ubuntu and Windows 8 and it works straight away when plugged in. Then no disconnects happen within hours too...

There is nothing connected to my Pi apart from the USB dongle and I either ssh through ethernet (then there is a cable) or plug a monitor and a keyboard (with no ethernet cable). The commands' results listed below stay the same in both situations.

1. At the initial config setup I have turned on SSH and boot to desktop as the intent is to use the Pi headlessly.

sudo wpa_cli
wpa_cli v1.0
Copyright (c) 2004-2012, Jouni Malinen <j@w1.fi> and contributors
This program is free software. You can distribute it and/or modify it
under the terms of the GNU General Public License version 2.
Alternatively, this software may be distributed under the terms of the
BSD license. See README and COPYING for more details.
Selected interface 'wlan0'
Interactive mode
<3>CTRL-EVENT-SCAN-RESULTS
<3>CTRL-EVENT-SCAN-RESULTS
<3>CTRL-EVENT-SCAN-RESULTS

it could help, if you connect the adapter not directly to the pi, but by a usb-hub. I had similiar problems here, and this solved spurious problems. Unfortunately, from the three usb-hubs I own, only one works reliable for this purpose. So some experiments might be needed.

Thanks Gerhard, I don't have a usb hub and frankly would rather request a device exchange if that is proven to be the problem. Hopefully can borrow one soon so to test. Meanwhile, I would like to debug further in order to find the root cause; however, I do not know how to proceed from here...

Check your power supply. If the PS cannot supply enough current, then the WIPI will drop out then try to connect then drop out repeating over and over.
If you have access to a volt meter measure the voltage on the test pads T1 (+5V) and T2 (ground).
You should have at least 4.75V and no more than 5.25V. Measure when WIFI is on or attempting to connect.
Or try a different PS.

I run my WIPI directly connected to USB port and my KB/mouse through a non powered hub with no problem. However if anything else is connected then you must move the WIPI to a powered hub.

1. Get a good power supply for your Pi. I recommend 5V 2A minimum for a wall wart, or go a solid 5V switching supply. I use a 5V 4A Meanwell switcher. The Pi MUST have solid power; many wall warts can't do much more than power the Pi by itself.

2. See note 1 - I can't emphasize this enough.

3. Depending on how much power your WiFi dongle needs from the 5V supply, it may or may not work directly in the Pi. The Pi only has so much extra power available before you trip the protection device. I am using an Airlink Golden 150 WiFi dongle and I can plug it into either the Pi itself or the generic USB hub. Both work equally well (now)...

4. Originally I could only make the WiFI work in the Pi, not the hub. Cheap Chinese hubs caused me to chase my tail for a while...

If you are using a USB hub, it MUST support USB 2.0. I don't care how the hub marked, the port must allow high speed as opposed to full speed operation. There are MANY counterfeit hubs that can't do USB 2.0 at all, some that can't mix USB 1.1 and USB 2.0, and a few that have the first port as USB 1.1 and the other three as USB 2.0 (I have a couple with NEC chips in them like this). Plus, your hub should be externally powered by a separate from the Pi. A high speed USB device is allowed (by spec) to pull up to 500mA, so the external supply should have 2A available on a 4 port hub.

5. After making allowances for the above (and getting the latest firmware for my distro) my Raspberry Pi operates far more smoothly with USB devices than it first did a year ago. Hot plugging used to be a recipe for reboots - I haven't seen that for months.

Hi, I am with the recommended adaptor from Element14 website. Only have one more for my cell phone and will give that one a try tonight. Is there a software way to monitor if the pi has supply issues? Furthermore, if the protection device was tripped then the Pi would reset - this is what happens when I hot plug the WiPi. This does not happen. It is just constantly scanning accordnig to wpa_cli.

nmadzharov wrote:Is there a software way to monitor if the pi has supply issues?

There may be a way to do this with software, but the quickest way is to use the two points on the PCB mark TP1 and TP2. Just pop a multimeter across the two points and you'll get the volts that the power adaptor is providing. Ideally you'd want 5v.

Go to your router and check which encryption is enabled in the wireless security settings. Make sure the encryption is matched on the RPi. TKIP or CCMP.
Note: If your router is set to AES then set CCMP on the RPi.

The problem is back!
I have removed any authentication required from the network and the WiPi is still stuck in constant "scanning" and not finding anything nor connecting. Please suggest steps to debug as the Pi remains useless

Everything works fine for about an hour, network settings, you name it, updated itself, installed a bunch of add-ons then bang the wi-fi just stops working, blue wi-fi adapter light goes out right after the boot screen before going into XBMC and in RaspBMC settings (via XBMC) there is not network settings anymore.

Further I re-imaged it today with RaspBMC, worked fine for an hour, then wi-fi dies...